Blenders are kitchen appliances designed for mixing or blending food ingredients such as fruits, milk and ice, into liquids. Blenders typically consist of a base, having a vertically positioned powerful a/c motor with a first coupling, and a cylindrical jar located directly above the base. The jar has a rotatable blade assembly at the bottom with a second coupling driven by the first coupling.
Blenders comprising means for heating the ingredients in the jar are known. A first version of this type of blenders comprises a jar made of metal, a heating element integrated in the jar and an electrical connection between the base and the jar for powering the heating element. Another, less common version of this type of blenders includes a jar made of glass material and a heating element disposed in the base. The heating element heats a bottom part of the jar by heat conduction, and therefore no electrical connection is provided between the jar and the base. This latter type of blenders has the advantage of providing a full transparency of the jar and a sense of quality to the user, and also allows the jar to be machine-washable since the jar does not have any electrical connection.
In order to achieve an effective cooking of the food ingredients, without undercooking, overcooking, overflowing or dry-boiling, it is useful to provide a temperature sensor in the blender to measure the temperature in the jar and provide a temperature feedback to the base. One problem with measuring the temperature in the jar is that the temperature sensor cannot be directly in contact with the food ingredients. One solution is to sense the temperature through the glass wall of the jar or on an extended lip coming out from a blade holding component of the jar. However, this solution gives a reading of the temperature in the jar that is delayed and therefore not accurate.
US2008/0264270 discloses a baby food maker comprising a jar having an open top and an open bottom for holding food. A top cap is provided for closing the open top of the jar and a bottom cap sealingly engages with the lower end of said jar for forming a cooking chamber. A blending means is installed inside the cooking chamber for blending food and a heating tube is fixedly installed on the bottom of the bottom cap for heating food.
US2015/0101491 discloses a soup maker comprising a container mounted to an annular seat receiving a heat conducting pan that receives food to be cut by a cutter. A heating pan abuts a bottom of the thermally conducting pan and is connected to a heating tube which is electrically connected to a power supply terminal. A temperature sensor abuts the heating pan. The soup maker comprises a base including a coupling portion having a terminal hole and a sensor hole.
US2008/0035630 discloses a cooking device comprising a coupling housing having a detachable vessel with a detachable pulverising blade, a sensor and a plate type of a heater on which a plurality of heat bands are installed to adjust the calorific value. A base is coupled to the lower part of the coupling housing.